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donahue_85
06-05-2009, 04:59 PM
I have a 1986 15' 4" Hydra-Sports Bass Boat. It is rated to handle a 75 maximum HP. I am going to put a 120 V4 Johnson on it. I am curious to know if I will be okay with this engine. I don't want to get it out there & something bad happen. I appreciate the info!! :confused:

I know that if this thing works okay, my boat should almost take off & fly at WOT!

wogi
06-07-2009, 11:03 AM
On this website I dont think "engine to big" has ever been asked! I think you will be fine, just stay away form the water natzie's or lose the factory rating plate. Just my 2cents:leaving:

jetwash127
06-07-2009, 11:43 AM
I don't think there is such a thing as engine too big!!
Just keep a eye on engine mounts and transom.

donahue_85
06-07-2009, 04:30 PM
As I said, my main concern is about weight & torque. My boat has never had any kind of work done preping it for this kind of HP, so I don't want to get out there & it fall apart on me! I thought I should be okay too, but I really want some other opinions. Please keep them coming!!!! Let me know if this is a good or bad thing. I will be a pissed MF'er if this thing falls the F apart on me! Not y'all's fault by any means, but I really want to make sure I'm atleast 3/4 safe before I take the kids fishing & stuff. Thanks a lot for the input!! It does help!


I don't know if any of you are from the Charlotte Harbor area, but I have some friends that own a fiberglass repair shop here called All Fiberglass Repairs, they are quite knowledgeable & helpful. They have given their opinions & all seems good in their eyes. Please, if you have any objections, tell me now!!! Before I mount the motor & haul ass!!

donahue_85
06-07-2009, 04:38 PM
Wogi, what do you mean by the water nazi's? FWC? They have never stopped me before, but with this much power, I WILL be stopped sooner or later.

donahue_85
06-07-2009, 04:42 PM
Jetwash, thats the thing, I don't want to have to worry about looking back at the transom to see if it will fall off. I would like to run a jack plate, but the cost of one is an issue for me. I'm on a strict budget!! The wife won't allow much more than what I've already spent.

cltch
06-07-2009, 05:07 PM
How thick is the transom? Is it solid? Do you have knee braces running from bottom/stringers to the transom? If you go with a jackplate and the motor you may want to look at adding knee braces if not already there, and they couldn't hurt the process now with just the motor. But, as far as overpowering, it is quite frequent on here! Goodluck! Keep us posted how it goes!

donahue_85
06-08-2009, 11:18 PM
I will let you guys know how it turns out. I plan on mounting the engine this coming weekend if I get a chance. As for the stringers, I have no idea what is in there. I've never tore into the hull to see what the inside is like. I get what you mean about the braces though, not a bad idea. Only problem I have is that my batteries & fuel cell are right there in the way of where I would have to do said work. I'm pretty sure it should be okay, but as I stated before, I really like second opinions! I might try to get in there & take a look to see if it looks good for sure.

grendle
06-10-2009, 10:33 AM
i was thinking about going to a 200 on my bass boat (because there are several available here ) would removing all hp engine badges be a simple effective way to hide it ? the boat is rated for a 175 and has a 150 on it now.

KingRootinTootin
08-14-2009, 10:59 AM
I have a 1986 15' 4" Hydra-Sports Bass Boat. It is rated to handle a 75 maximum HP. I am going to put a 120 V4 Johnson on it. I am curious to know if I will be okay with this engine. I don't want to get it out there & something bad happen. I appreciate the info!! :confused:

I know that if this thing works okay, my boat should almost take off & fly at WOT!

i think a merc 150 XS would be a better choice:cheers:

but seriously, Enjoy!

wideglide55
08-14-2009, 09:08 PM
If it still floats when you launch it then it ain't too big.I knew a guy with a 19ft Laser that had a V/8 OMC on it,he stopped to pee one day and walked back to stand on the transom,it looked like it was ready to sink!

BUSHWACKER
08-15-2009, 04:18 AM
Being your rite there, take it over to Scott let him check it out for ya. :thumbsup:

antic55
08-23-2009, 06:58 AM
This is me and a mate going for a ski behind his old mans boat. 1750 Bullet with a 300 promax its a lot of engine for a 17.5ft boat haha

mickeyjr
08-30-2009, 09:45 PM
This is me and a mate going for a ski behind his old mans boat. 1750 Bullet with a 300 promax its a lot of engine for a 17.5ft boat haha

how well does that boat run? neat pic.

antic55
08-30-2009, 10:23 PM
Boat only 98.6mph and with two skiers 86.something. it was pretty quick anyway

HydraSports
11-07-2009, 11:16 AM
The transom, if in good shape, looks to be a pretty strong design. I also have a Hydrasports bass boat and am going to build an aluminum brace for the transom...The boat is 17'2" rated for a 150 (with a XP150 on it)....The plan is to eventually slap a build 235 crossflow powerhead onto the mid/lower I have.

Adding some stuff to make the boat safer, and easier to drive this winter. Steering trim, Hot Foot, solid motor mounts....Then I want to get a GPS'd run and adjust things using the 6" Jackplate.

Then I'm going to add a nose cone and a exhuast dump, and GPS it again....Everyone say's no gain but I gotta see for myself.

Keep us updated on how the boat handles and runs.

tunnels
01-03-2010, 03:44 PM
I changed my old 70 hp omc for a 115 yamaha and had no problems just have to hang on tighter and dont wear a hat , lost a couple so far !!:thumbsup:

Team Brown Stripe
04-26-2010, 10:26 PM
My 16' Dynatrak is rated for a 115 but I put a 120 looper on it and added some 115 stickers. Then I did the mods to it to make it a 140 (4-225hp carbs, Intake, 6 pedal boyesen reeds & reed boxes) + milled heads so all 4 pistons are at 150psi. So it is about 150 hp and it is a lot of fun. I have no issues with floating it either. I am trying to get with S&F member Way 2 Slo on H20 and put it on his Dyno and EGT's to set it up perfectly.

BTW, I also added a 6" Jackplate set 4"s above the transom and plugged the top holes in the lower unit.

BEFORE

http://i11.photobucket.com/albums/a178/tcfarmer/DSC02133.jpg

AFTER :)
http://traclan.clanservers.com/DSC00179.JPG

tunnels
04-26-2010, 11:31 PM
Live life short and fast , make sure your insurance is paid up for the family then you wife wont care how fast you run!!!!:cheers: :D :cheers:

Team Brown Stripe
04-27-2010, 08:36 AM
+1 Its fun but it can get DANGEROUS QUICKLY!!! Remember to wear your PFD and hook up your killswitch EVERY TIME you get it wet!!! Boats that short have a hard time in rough water but it gets WAYYYYY worse over 60mph!!!


Live life short and fast , make sure your insurance is paid up for the family then you wife wont care how fast you run!!!!:cheers: :D :cheers:

JIM WEST
04-29-2010, 12:04 PM
I have a 1986 15' 4" Hydra-Sports Bass Boat. It is rated to handle a 75 maximum HP. I am going to put a 120 V4 Johnson on it. I am curious to know if I will be okay with this engine. I don't want to get it out there & something bad happen. I appreciate the info!! :confused:

I know that if this thing works okay, my boat should almost take off & fly at WOT!

I worked for a boat dealer back in the day when people did over power boats just to see what would happen.We had a 14 hydra sports and put a 150xs on it.I took it to the lake with a lot of props and that was a heart pumping after noon.The boat was a hand full to drive but it was fun.So i think the boat would hold the bigger motor ok but drive it like it will hurt you :thumbsup:

tunnels
04-29-2010, 12:42 PM
I changed my rig from a tired old 70 hp omc to a 115 V4 ,25 inch shaft yamaha,up the prop pitch a couple of inchs , built a 8 inch step back transom , Hydralic steering that keeps everything held tight with no slack ,now it fly's .
Yamaha speedo's dont go high enough cause it goes off the clock at 6200rpms , im the only person that drives it .
Damn it good to drive !!
I love my "LIL RUFF"
Life jackets are the only way anyone gets in the boat ! no jacket no entry !!
But its just a fishing boat !!:thumbsup:

Team Brown Stripe
04-29-2010, 12:49 PM
Yamaha speedo's dont go high enough cause it goes off the clock at 6200rpms

You mean a tach right? ;)
:iagree::iagree::iagree::iagree:

tunnels
04-29-2010, 01:11 PM
You mean a tach right? ;)
:iagree::iagree::iagree::iagree:

The last reading is speedo is 80kms and the needle disapears way past that !! my guess is possibly 110kms (getting close to 55/60 mph ) Damn good !!
See the picture on my avatar!!:D

Team Brown Stripe
04-29-2010, 02:24 PM
What pitch prop are you turning?

tunnels
04-29-2010, 02:49 PM
What pitch prop are you turning?

I had a 13 1/2 x 18" , the first time i used the boat with the bigger motor it jumped out of the water and took off straight up to 6200 and scared the pants off me , i went to my friendly local yamaha shop and asked if they could wind the rpms down a little ,they suggested a bigger prop to knock the top off the rpms , now i have a 12 1/2 x 21 it is slower at the lower revs but from about 3000rpms up it starts to bite and it really goes like stink and still goes to 6200 rpms , now i have had some seat time and got used to what it can do its fantastic !!. :cool:

Stage two i want to do some hull bottom mods to make the hull get out of the water quicker and really make it go .The old hull is good ,sound and solid but being a 1975 technology has changed and having worked on race boats for a while i understand all about what makes hulls tick and how to fine tune for safety and speed . :D
All this will have to wait a while till i get back from working in China !!:thumbsup:

regmcguire
10-28-2010, 09:00 PM
I would second the "check the transom" comments. I put a 200 Optimax on my 18' Baja this summer (old boat, but has been rebuilt) replacing a mid-80's Johnson 175. I also put a 6" hydraulic transom jack on, and the transom was moving around and cracking the gel coat with the motor lifted at all. I ended up having to get some pretty strong knees put in plus get the transom/deck joint reinforced to settle it down.

Great to drive now, much better engine than before, but the boat was not ready for the weight of the new motor and stress of the jackplate.

Boat still floats, almost like before, so clearly not too much motor. We did "lose" the rating plates years ago...